1. Field of the Invention
The present invention concerns authorized printing wherein a hard-copy image is printed only in the presence of an intended recipient. In particular, the invention concerns encryption of print data by a print node, and storing the encrypted print data without printout until the print node receives proper authentication from the intended recipient
2. Description of the Related Art
In a network environment, a print job generated at one location in the network can be printed at another location. Occasionally, confidential or otherwise sensitive information has to be printed. When the confidential information is transmitted to the printer, the sender may want to protect the data transmission over the network from electronic interception or at least prevent unauthorized viewing of the hard-copy printout. Generally, common encryption protocols such as SSL or TLS can be used to provide the required security from electronic interception of the transmission. Nonetheless, concerns remain about unauthorized viewing of the hard-copy printed output or electronic viewing of print jobs stored in the print queue.
In particular, if a print job containing confidential information is sent to a printer, the sender may not be present at the printer when the image is printed. During the time that it takes the sender to reach the printer to pick-up the hard-copy print job, the printed output can be viewed by any person who comes across the printed output before the sender has reached the printer. As a result, confidential information may be compromised by being viewed by an unauthorized person.
In addition, if the sender reaches the printer before the printer prints the image, and numerous print jobs are pending in the print queue before his, the sender would have to wait until all previously pending print jobs are printed before he can obtain his print job. As a result, the sender must either spend time waiting for his print job to print out or return later. In the latter case, the sender risks the possibility that his confidential print out will be printed before he is able to return.
Further, print jobs that have been stored in a file (local to the printer or in a remote file server) prior to printout are subject to electronic viewing by unauthorized personnel. Therefore, the stored print data must also be protected from unauthorized viewing.
Similar issues arise with a facsimile transmission. Namely, the printed output can be viewed by any person who arrives at the destination facsimile machine before the intended recipient.
Therefore, a method of printing an image only in the presence of the intended recipient and securely storing print data is needed.
One method of printing a document only in the presence of the intended recipient is disclosed in U.S. Pat. No. 5,633,932. According to the patent, a sending node encrypts a print job and a printing node decrypts the print job prior to printout. If the print job contains confidential information, the sending node generates an encrypted header signifying that fact, using a public key of the printing node. The printing node contains its own private key, and upon receiving the encrypted print job, decrypts the header to ascertain whether the document requires authentication by the intended recipient before printing. If so, the print data is stored without printout in encrypted form until the print node receives the proper authentication from the intended recipient. If the print node determines that the document does not require authentication, the print node decrypts and prints the document.
The present invention also ensures that printout of sensitive documents is authorized and that the print data is securely stored, but it does so in ways that are different from the aforementioned U.S. Pat. No. 5,633,932.